James Armour Johnstone (25 June 1859–8 May 1933) was a New Zealand businessman and stock breeder. He was born in Glasgow, Lanarkshire, Scotland on 25 June 1859. Johnstone's father, David, was a Congregational minister. In 1868 he, his wife Jessie, and their four children moved to Dunedin, New Zealand. After attending high school, James Johnstone joined the stock and station agency Wright Stephenson and worked his way uip through the business from office boy to stock agent, and by 1885 his business skills saw him made a partner in the business. In 1899 he became senior partner and became chairman of directors when the company was publicly listed in 1906.